What is theback spacing/offest is on my 9.5" wide ZR1 wheels? What is the back spacing on the 9.5" Grand Sport wheels? TIA.

 

http://www.skulte.com/adapterfaq.html

Various Rim Dimensions

Rim Name Size Offset Backspacing Suggested Thickness (3rd Gen)
Corvette 84-87 16x9.5 38mm 6.6" 2"
Corvette 88-96 17x9.5 56mm 7.3" 2.25"
Corvette GS ZR1 style 17x9.5 50mm 7" 2"
Corvette ZR1 style (Low Offset) 17x9.5 38mm 6.7" 2"
Corvette ZR1 style (Low Offset) 17x11 36.5mm 7.397" 1.25" Rear
Corvette ZR1 style (High Offset) 17x9.5 56mm 7.4" 2.25"
Corvette ZR1 style (High Offset) 17x11 50mm 7.93" 2" Rear
C5 Corvette 97-2000 17x8.5 front 56mm 6.8" 2"
C5 Corvette 97-2000 18x9.5 rear 63mm 7.6" 2"
C5 Corvette Z06 17x9.5 front 54mm 7.2" 2.25"
C5 Corvette Z06 18x10.5 rear 58mm 7.9" 2" Rear
Camaro 82-92 16x8 front 0mm 4.35"
Camaro 89-92 16x8 rear 16mm 5"
Camaro F1 ZR1-style 17x9 50mm 6.8" 2"
Camaro 93-97 16x8 55mm 6.5" 2"
ROH ZS 17x9.5 5 mm 5.472"
ROH ZS 17x8.5 -7 mm 4.5"

 

Offset is +56mm
BackSpacing is 7.4"
Lug Pattern is 5x120.65mm

Hope this helps.

 

Thanksguys, that helps alot. Please excuse my ignorance, but would the same wheel with a 56mm offset stick out more than a wheel with a 50mm offset, or vice versa?

 

The 50mm wheel is going to stick out 6 mm more than the 56mm wheel.